A Patient's Guide to Ultrasound Scans

Ultrasound scans are among the most common imaging tests. Here is what they involve.

How it works

A sonographer moves a small handheld device, called a transducer or probe, over your skin. It sends out sound waves too high-pitched to hear. The echoes bounce back from tissues and organs, and a computer turns them into moving images on a screen. A water-based gel helps the sound pass between the probe and your skin.

Common types of scan

• Abdominal: looks at organs such as the liver, gallbladder and kidneys.
• Pelvic: looks at the bladder and reproductive organs, sometimes from outside and sometimes internally.
• Pregnancy: checks the pregnancy at different stages.
• Musculoskeletal: looks at muscles, tendons and joints.
• Vascular: checks blood flow in veins and arteries.

Typical preparation

Each clinic sets its own rules, so check your letter. Common examples:

• Not eating for a few hours before an abdominal scan
• Drinking water so your bladder is full for a pelvic scan. See why a full bladder helps.
• No special preparation for many muscle, joint and vascular scans

On the day

You may be asked to change into a gown or uncover the area. You’ll lie on a couch, often with the room dimmed so the screen is easier to see. The sonographer applies gel and moves the probe, sometimes asking you to hold your breath or turn. Internal scans are explained first, and you can ask for a chaperone.

Afterwards

You wipe off the gel and can usually go back to normal activities straight away. Read when results arrive and whether ultrasound is safe.

This is general information, not medical advice. Always follow the instructions from your own care team.